Copulation Test
Objective: To measure extracellular dopamine levels in the medial preoptic area (MPOA) during precopulatory exposure to estrous females and during copulation in male rats, and to determine the relationship between dopamine activity, sexual motivation, and hormonal control of copulation
Gather these items before starting the experiment. Check off items as you prepare.
Equipment3
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Protocol Steps
Precopulatory exposure phase
Male rats were exposed to an estrous female with a barrier between them to prevent copulation
Note: Dopamine levels were measured during this phase in all animals
View evidence from paper
“DA level increased during precopulatory exposure to the female in all animals that subsequently copulated”
Barrier removal and copulation
The barrier was removed allowing male and estrous female to copulate while dopamine levels continued to be measured
Note: Dopamine and metabolite levels were monitored throughout copulation
View evidence from paper
“When the barrier was removed and the animals were allowed to copulate, levels of DA and its metabolites continued to rise”
Male exposure control
In separate trials, male rats were exposed to another male instead of an estrous female to test whether dopamine response was specific to sexual stimuli
Note: This served as a control for nonsexual social stimuli
View evidence from paper
“The DA response to the estrous female could not be attributed to nonsexual social stimuli, since exposure to another male was ineffective”
Voluntary running control
Male rats were allowed to run voluntarily in a running wheel while dopamine levels were measured
Note: This control tested whether increased dopamine during copulation was due to motor activity alone
View evidence from paper
“animals running voluntarily in a running wheel did not show significantly increased DA”